Perhaps others already use this and I have simply missed your mention of it, but in case its new to you too, I strongly suggest you check it out. There are an incredible number of interesting searchable texts available. Heres a direct link to perhaps the most useful area for this board:

http://www.questia.com/Index.jsp?CRID=word_origins&OFFID=se1&KEY=word_origin


This takes you to the front end of all kinds of other topic searches!

http://www.questia.com/Index.jsp